HP-UX 9

HP-UX is a Unix variant based off of System III, later System V Unix. Released in 1984, the initial version of HP-UX supported the Motorola 68k processor family, specifically the HP 9807A, the "HP Integral PC". This OS is still updated, with its latest being version 11i. Platforms that HP-UX have ran on were the Motorola 68k, RISC, HP FOCUS, and the Itanium family of Intel processors.
HP-UX was the first UNIX to provide access control lists (acls), logical volumes, features that are currently supported by newer mainstream Operating Systems.
HP-UX versions before 11.0 are not deemed as being Y2k-compliant by HP.